Hammer driving means in high speed printers



A. B. BRADEN, JR, ETAL 3,

HAMMER DRIVING MEANS IN HIGH SPEED PRINTERS 4 Sheets-Sheet 1 March 30, 1965 Filed se t. 14, 1962 INVENTORS ARTHUR B.BRADEN JR. ROBERT L.KLEEKAMP CLARENCE LANDERSON BY W THEIR ATTORNEYS March 30, 1965 A. B. BRADEN, JR., ETAL 3,175,437

HAMMER DRIVING MEANS IN HIGH SPEED PRINTERS Filed Sept. 14, 1962 4 Sheets-Sheet 2 INVENTORS ARTHUR B.BRADEN,JR. ROBERT L.KLEEKAMP NIYAZI AYGUN THEIR ATTORNEYS CLARENCE LANDERSON March 30, 1965 A. B. BRADEN, JR, ETAL 3,175,487

HAMMER DRIVING MEANS IN HIGH SPEED PRINTERS 4 Sheets-Sheet 3 Filed Sept. 14, 1962 FIGS FIG.7

Aw w W N R E EM E N SD D R RAE N 0 ORENA T B UL T N .KG A. EB YE R v Ac mm m HEMR T TwvlA ARNC March 30, 1965 A. B. BRADEN, JR, ETAL 3,175,487

HAMMER DRIVING MEANS IN HIGH SPEED PRINTERS Filed Sept. 14, 1962 4 Sheets-Sheet 4 INVENTORS ARTHUR B. BRADEN,JR. ROBERT L. KLEEKAMP NIYAZI AYGUN CLARENCE LANDERSON THEIR ATTORNEYS United States Patent 3,175,487 HAMMER DRIVING MEANS IN HIGH SPEED PRINTERS Arthur B. Braden, Jr., Robert L. Kleekamp, Niyazi Aygun, and Clarence L. Anderson, Dayton, Ohio, assignors to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland Filed Sept. 14, 1962, Ser. No. 223,644 12 Claims. (Cl. 101-93) This invention relates to a high-speed printer and, more particularly, to such printers in which a plurality of the printing elements are in continuous motion.

The translation of computed information from electrical signals to printed characters has been one factor limiting computer speeds. High-speed printers having continuously-moving printing elements, often termed onthe-fiy printers, have been devised which have many advantages. For example, continuously-rotating type wheels or drums may cooperate with selectively-actuated ham- Iners to provide rapid printing, a number of these hammers ordinarily being laterally disposed to print lines of characters. It is apparent that the several printing hammers, one for each column, must be closely synchronized in their actuation to preclude faulty alignment of the printed characters.

' Previous printing arrangements having a continuouslyrotating type wheel have included a solenoid or other electromechanical device operating directly to cause the hammer to force the recording medium against the type wheel. However, not only does this arrangement require a great amount of electrical power, being the printing energy source operating through an inefiicient transducer, but it requires a high degree of electrical timing synchronization in order to obtain adequate print quality. For example, if a high degree of electrical timing synchronization is not maintained, objectionable misalignment of the printed lines may result.

In an effort to insure that the printed characters are accurately aligned, printers have been proposed in which continuously-moving character-carrying members are synchronized with actuating hammers. One such printer is disclosed in United States Patent No. 2,895,411, issued to Frederick M. Demer and Richard H. Harrington on July 21, 1959. In that patent, a firing pin is disposed adjacent to a continuously moving type wheel. A plurality of hammers rotated in synchronism with the type wheel are normally held out of engagement with the firing pin by associated latches. Upon reception of a printing impulse, one of the hammers drives the firing pin against a selected character on the type wheel.

Another such printer is disclosed in United States Patent No. 2,897,752, issued to Gustav V. A. Malmros and Richard H. Harrington on August 4, 1959. In that patent, a firing pin is disposed adjacent to a continuouslyrotating type wheel. A plurality of hammers rotating synchronously with the type wheel normally pass the end of the firing pin. Upon receipt of an actuating impulse, the firing pin is moved momentarily into the path of the hammers and thereby driven against a selected character on the type wheel to print it on suitably-positioned datareceiving means.

It is highly desirable that a high-speed printer for utilization as an output device in a computer system be capable of being controlled or operated by electrical signals of a power or voltage close to the low voltage and current electrical signals used in the computer itself to perform logical operations. Even though the above-mentioned printers possess many desirable features, they still require electrical signals of an appreciable amount of power or voltage for their control or operation. Accordingly, a good deal of electrical amplification is necessary to raise the low-power electrical signals used in a computer at logical levels to a voltage or current sufiicient to don trol or operate the above-mentioned printers. The printer provided by the present invention is capable of being controlled or operated by electrical signals of a power or voltage closer to the low voltage and current electrical signals used in computers to perform logical operations. Since less electrical amplification of the low voltage and current electrical signals used at computer logical levels is necessary prior to use of these electrical signals for control or operation of the printer, applicants printer is believed to be more eificient and less expensive than pre vious known printers.

It is therefore an object of the present invention to provide a high-speed printer which is relatively inexpensive in that it requires a small amount of electrical power or voltage for the control or the operation thereof.

It is another object of the present invention to provide a high-speed printer which is highly efficient.

It is a further object of the present invention to provide a high-speed printer which is controlled or operated in a novel manner.

These and further objects of the invention are accomplished by disposing a printing hammer adjacent to a continuously-moving type wheel. A rotating element synchronized with the type wheel carries a plurality of hammer drivers pivoted on the rotating element and held inwardly by centrifugal force. An interposer is positioned adjacent to the rotating element. Upon reception of an actuating or printing impulse, an interposer-moving means operates to move the interposer between the printing hammer and a selected one of the hammer drivers. The interposer in this interposing position causes the selected hammer driver to move the hammer against the type wheel, resulting in the printing of a selected character on data-receiving means interposed between the type wheel and the printing hammer. The interposer-moving means comprises an electromagnet, an associated armature, and means resiliently urging the armature away from the electromagnet towards the rotating element. The armature is coupled to the interposer and is normally held by the electromagnet away from the rotating element. The electromagnet is responsive to an electrical printing signal to cause release of the armature, thereby allowing the urging means to move the armature towards the rotating element, whereby the interposer is moved between the printing hammer and the selected hammer driver. The interposer, upon being moved between the printing hammer and the selected hammer driver, causes the selected hammer driver to move the printing hammer against the type wheel, resulting in the printing of a selected character on the data-receiving means interposed between the type wheel and the printing hammer. After the printing of the selected character on the data-receiving means, the selected hammer driver operates to remove the interposer from between itself and the printing hammer, causing the armature to be moved away from the rotating element and adjacent to the electromagnet. The electromagnet operates to again hold the armature away from the rotating element until the reception of another printing signal.

In one specific embodiment of the invention, the rotating element or hammer driver assembly comprises (a) a pair of coaXially-spaced similar rotating Wheels or discs, (b) a plurality of hammer drivers pivotally mounted between the wheels at spaced positions adjacent the peripheries of the wheels and carried along a circular path, and (c) a rotating member between the wheels, coaxial therewith, preventing movement of the hammer drivers beyond predetermined limits. An interposer carrier which carries a slidably-mounted interposer is provided adjacent to the circular path. Upon reception of a printing signal, an interposer-moving means operates to move the interposer into the circular path between the printing hammer and a selected one of the hammer drivers. The interposer, in.

this interposing position, cause-s the printing of a selected character on a suitable data-receiving means.

The above and further objects and advantages of the present invention will be more readily understood when the following description is read in connection with the accompanying drawings, in which:

FIGURE 1 is a side elevation view, partly in section, of one printing mechanism located at a single station of a high-speed printer, which printing mechanism embodies the principles of the present invention;

FIGURE 2 is a sectional view taken along section line 2-2 of FIGURE 1 and shows the cooperation between the printing hammer, the interposer carrier, the interposer, the solenoid armature, and a hammer driver of the v instant apparatus;

FIGURE 3 is a side elevation view showing the .printing mechanism after a character has been selected and the print cycle has been started by release of the solenoid armature;

FIGURE 4. is a side elevation view showing the printing mechanism at the time of impact between the interposer and the selected hammer driver;

FIGURE 5 is a side elevation view showing the printing mechanism at a-slightly later time during the print cycle to illustrate the transfer of energy to the hammer and the resetting of the solenoid armature;

FIGURE 6 is a side elevation view showing the printing mechanism at the time of character impression;

FIGURE 7 is a side elevation view showing the printing mechanism after the print cycle has been completed and the selected hammer driver is being reset by the action of centrifugal force; and

FIGURE 8 is a perspective view showing the relationship of elements of the printing mechanism causing printing.

Referring now to FIGURE 1, there is shown a printing mechanism for a single station or columnar position. Any desired length of printed line can be obtained, within practical mechanical limitations, by the addition of additional printing mechanisms for each column of characters, or symbols, that is desired. The shaft 10 is continuously rotated clockwise. Fixed to the shaft 11 are the type wheels 11, one per column position. Gears 12, 13, 14, 15, and 16 synchronize the angular relationship of the type wheel shaft 10 to the hammer driver assembly shaft 17. The gear 14 is the driving pinion and provides the source of driving torque for the printer.

A series of discs or wheels 18 are fixed to the shaft 17 and spaced alternately with hammer driver stop discs or cams 19, each pair of outer discs 18 and its central stop disc 13 forming a part of a hammer driver assembly. A hammer driver assembly is provided for each of the type wheels 11. The two outer discs 18 provide spacing for the central stop disc 19 and bearing pivot holes for each of the hammer drivers 20. The stop disc or cam 19 is provided with twelve lobes 21. In each cavity 22 formed by the lobes 21 of the stop disc 19 is pivotally mounted a hammer driver 20 on a pivot pin 23. The cavity allows free rotation of a hammer driver 29 to two stop positions in the stop disc 19. These two stop positions are defined by two stop surfaces 24a and 2412 provided on each of the lobes 21 of the stop disc 19. Twelve hammer drivers 20 are provided for each hammer driver assembly. The hammer drivers 20 are pivotally mounted by the pivot pins 23 between the discs 18 at spaced positions adjacent t'otheir peripheries and are carried along a circular path. The hammer drivers 219' are mounted in relation to the stop surfaces 240: and 24b of the lobes 21 of the stop disc 19, so that each can swing through approximately ninety degrees outwardly from the discs 18. The hammer drivers 20 are so designed that their center of mass is located tothe right or the pivot pin 23 regardless of their 4L rotational position throughout a print cycle. The hammer drivers 26 are rotated about the shaft 17 in a counterclockwise direction and at a constant angular velocity, so that the normal acceleration through the center of mass of each hammer driver 20 will retain the hammer driver 20 against the closed position stop surface 24:: of the stop disc 19 unless an external force is applied.

A printing hammer 25 is provided for each of the type wheels 11. Thehammer 25 is pivotally mounted on the shaft 26 and is biased by the spring 27 to a position in which one end 28 is adjacent to the printing position and its other bifurcated end 29 (FIGURES 2 and 8) is against an interposer carrier 30. p e

The interposer carrier 30 is pivotally mounted on the shaft 31 adjacent to the hammer driver assembly and is provided with a first slot 32 (FIGURES 2 and 8) running perpendicular to the axes of the shafts 17 and 31 and a second slot 33 (FIGURES 2 and 8) running perpendicular to the first slot 32.

The printing hammer 25 and the interposer carrier 30 are urged against a stop surface 34 (FIGURE 2) of a fixed bar 35 by the spring 27, which establishes the normal position for these elements.

A drop-out type of electromagnet with its associated armature is provided for each of the hammer driver assemblies. The electromagnet 36 and the armature 37 are provided for the hammer driver assembly shown in the drawings, while the electromagnet'38 and the armature 32 are provided for the next hammer driver assembly in the series along the shaft 17. V

Each of the electromagnets 36 and 38 is similar. The

electromagnet 36 comprises a core 46, about which a plurality of operating coils (not shown) are wrapped. One or more of the operating coils serve as a holding coil. The holding coil, when energized, produces a magnetic flux sufficient to hold the armature 37 in a' position adjacent to the core 46 after it has been moved to that position by a selected hammer driver 20 following a print operation. Since the electromagnet 36 attains maximum magnetic force in its air gap when the air gap is closed, a minimum amount of continuous electrical power is necessary in order to generate sufficient magnetic flux to oppose the urging of a flat leaf spring 43, which is suitably attached to a bar 44.

One or more of the remaining operating coils serves as an opening or drop-out coil. The opening coil, when energized, produces a magnetic flux in opposition to the flux produced by the holding coil, thus neutralizing the holding coil and allowing the armature 37 to be released under the urging of the spring 43.

Since the magnetic flux established by the holding coil is minimal, the electrical signal to cause sufiicient current in the opening coil to create the neutralizing flux in the air gap is also very low. Iris apparent, therefore, that the electromagnet 36 is being used in its most efficient manner. 1

A rectangular slider or interposer 40 having anaperture 50 therein (FIGURE 8) isslidably mounted in the slot '33 of the interposer carrier 30. One end 41 (FIGURES away from its interposing position. The armature 37 is urged towards the circular path of the hammer drivers 20 against the stop surface 42 of the bar 35 by the spring 43. The electromagnet 36 is normally energized to provide sufficient magnetic holding force to overcome the urging force of the spring 43 and hold the other end 45 of the. armature 37 adjacent tothe core 46 of the electromagnet 36. A very small air gap is maintained by the use of a. rigid stop bar 47, which prevents the armature 37 from closing completely against the core 46 of the electromagnet 36. Accordingly, the normal position of the armature 37 holds the interposer member 40 out of the circular path of the hammer drivers and clear of engagement therewith. The armature is pivotally mounted on a fixed shaft 48 and is movable between the limits set by the stop bars 35 and 47.

When a selected character is to be printed, the electromagnet 36 (opening coil or coils thereof) is further energized at the appropriate time, so that its electromagnet field will decay and allow the spring 43 to move the armature 37 counter-clockwise against the bar 35 and bring the interposer member 40 into the circular path of a selected hammer driver 20, as shown in FIGURE 3. In FIGURE 4, the interposer member 40 is shown engaged with the selected hammer driver 26, and energy from the selected hammer driver 20 is beginning to be transferred to the printing hammer through the interposer carrier 30. In FIGURE 5, the selected hammer driver 29 has begun to rotate on the pivot pin 23 away from the stop surface 24a of the stop disc lobe 21 as a result of the rotation of the shaft 17 and the interference of the interposer member 40. The armature 37 has begun to move toward the bar 47 and the face 46 of the electromagnet 36. At this time, the printing hammer 25 is attaining a high velocity and is moving toward the type wheel 11 and a round, eccentrically-mounted bar 49 (FIGURES 3 and 7). The bar 49 prevents the end 28 of the printing hammer 25 from striking the surface of the type wheel 11, but it is adjusted so that the necessary pressure is exerted on the data-receiving means 50 for transfer of ink thereto from an inking ribbon (not shown). The bar 49 also provides a rapid rebound for the printing hammer 25, so that character delineation is improved and the printed character is not smudged. As further shown in FIGURE 6, the selected hammer driver 20 has rotated further on its pivot pin 23 to its open position against the open stop surface 241; of the stop disc lobe 21, and the selected hammer driver 20 has moved the interposer 40 away from the peripheries of the discs 18, causing the armature 37 to be lifted against the stop bar 47, so that the re-established magnetic field of the electromagnet 36 can restrain the end 45 of the armature 36 closely adjacent to the face 46 of the electromagnet 36 against the urging of the spring 43. In FIGURE 7, the interposer carrier has been moved against the stop surface 34 of the bar in response to the rebound of the printing hammer 25 from the impact control stop bar 49 and the urging of the spring 27. The interposer carrier 30 engages the stop surface 34 of the bar 35 after the selected hammer driver 20 has rotated completely against the open stop surface 24b of the stop disc lobe 21 (FIGURE 6), allowing the interposer to be cleared from the selected hammer driver 20. Since the mass center of the selected hammer driver 20 is still to the right of the line between the pivot pin 23 and the center of the shaft 17, centrifugal force will urge the selected hammer driver 20 toward its closed, or restored, position against the closed stop surface 24a of the stop disc lobe 21, and it will move into its closed position (FIGURE 1) in less than one revolution of the hammer driver assembly on the shaft 17.

While the invention has been shown in a specific form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In a high-speed printer,

(0:) means carrying a plurality of characterspast a printing position,

(b) a printing hammer adjacent to said printing position adapted to urge data-receiving means against said characters,

(0) a rotating element synchronized with said character-carrying means,

(d) a plurality of stop elements associated with said rotating element, providing a plurality of pairs of stop surfaces,

(e) a plurality of hammer drivers pivoted on said rotating element and held inwardly by centrifugal force against one stop surface of an associated pair of said stop surfaces,

(f) an interposer positioned adjacent to said hammer and rotating element so that it can move between said hammer and a selected one of said hammer drivers,

(g) and means to move said interposer between said hammer and a selected one of said hammer drivers, said interposer operating to cause said selected hammer driver to move from said one stop surface and to move said hammer against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carrying means and said hammer, and operating to cause said selected hammer driver to be pivoted outwardly against centrifugal force against the other stop surface of said associated pair resulting in removal of said interposer from between said hammer and said selected hammer driver after printing of said selected character.

2. In a high-speed printer,

(a) means carrying a plurality of characters past a printing position,

(b) a printing hammer adjacent to said printing position adapted to urge data-receiving means against said characters,

(0) a rotating element synchronized with said character-carrying means,

(d) a rotating member mounted adjacent to said rotating element, coaxial therewith, providing a plurality of pairs of stop surfaces,

(2) a plurality of hammer drivers pivoted on said rotating element, each held inwardly against one stop surface of an associated pair of said stop surfaces by centrifugal force,

(f) an interposer positioned adjacent to said hammer and said rotating element,

(g) and means to move said interposer between said hammer and a selected one of said hammer drivers, said interposer operating to cause said selected hammer driver to move said hammer against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carrying means and said hammer, and operating to cause said selected hammer driver to be pivoted outwardly from said rotating element and away from said one stop surface against the other of said stop surfaces of said pair resulting in the removal of said interposer from between said hammer and said selected hammer driver after the printing of said selected character.

3. In a high-speed printer,

(a) means carrying a plurality of characters past a printing position,

(b) a printing hammer adjacent to said printing position adapted to urge data-receiving means against said characters,

(0) a rotating element synchronized with said character-carrying means,

(d) a multi-lobe rotating member mounted adjacent to said rotating element, coaxial therewith, each lobe thereof providing a pair of stop surfaces,

(e) a plurality of hammer drivers pivoted on said rotatterposed between said character-carrying means and said hammer, and operating to cause said selected hammer driver to be pivoted outwardly from said rotating element and away from said one stop surface against the other stop surface of said lobe resulting in the removal of said interposerfrom between said hammer and said selected hammer driver after the printing of said selected character 4. In a high-speed printer, 7

(a) means carrying a plurality of characters past a printing position,

(b) a printing hammer adjacent tosaid printing position adapted to urge data-receiving means against said characters,

(c) a rotating hammer driver assembly synchronized with said character carrying means comprising a pair of coaxially spaced similar rotating wheels, a plurality of hammer drivers pivotally mounted between said wheels at spaced positions adjacent the peripheries of said wheels and carried along a circular path, and a rotating member between said wheels, coaxial therewith, preventing movement of said hammer drivers beyond predetermined limits,

(d) a pivotally-mounted interposer carrier positioned adjacent to said circular path,

(:2) an interposer slidably mounted in said interposer carrier,

(f) and means to move said interposer into said circular path between said hammer and a selected one of said hammer drivers, said interposer operating to cause said selected hammer driver to move said hammer against said charactercarrying means resulting in the printing of a selected character on said datareceiving means interposed between said charactercarrying means and said hammer.

5. In a high-speed printer,

( a) means carrying a plurality of characters past a printing position, 7

(b) a printing hammeradjacent to said printing position adapted to urge data-receiving means against said characters,

(c) a rotating hammer driver assembly synchronized with said character-carrying meanscomprising a pair of axially spaced similar rotating wheels, a plurality of hammer drivers pivotally mounted between said wheels at spaced positions adjacentthe peripheries of said wheels and carried along a circular path, said hammer drivers movable between a closed position and an open position, centrifugal forces developed in said hammer drivers by hammer driver assembly rotation normally retaining said hammer drivers in said closed position, and a multilobe rotating member between said wheels, coaxial therewith, each lobe thereof providing a pair of stop surfaces for eachof said hammer drivers correspondingto said closed and open positions,

(d) a pivotally-mounted interposer carrier positioned adjacent to said circular path,

(e) an interposer slidably mounted in said interposer carrier, a V

(f) and tneans to move said interposer into saidcircular path between said hammer and a selected one of said hammer drivers, said interposer operating to cause said selected hammer driver to move said hammer against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carrying means and said hammer and operating to cause said selected hammer driver to move from said closed position to said open position allowing the removal of said interposer from between said,

, 6. In a high-speed printer,

(a) means carrying a plurality of characters-past a printing position, I

(b) a printing hammer adjacent to said printing posi tion adapted to urge data-receiving means against said characters,

(c) a rotating hammer driver assembly synchronized with said character-carrying means comprising a .pair of coaxially spaced similar rotating wheels, a plurality of hammer drivers pivotally mounted between said wheels at spaced positions adjacent the peripheries of said wheels and carried along a circular path, said hammer drivers movable between a closed position, in whicha hammer driver extends outwardly a first distance beyond the peripheries of said wheels, and an open position, in which a hammer driver extends a second distance, greater than said first distance, beyond the peripheries of said wheels, centrifugal forces developed in said hammer drivers by hammer driver assembly rotation normally retaining said hammer drivers in said closed posit-ion, and a multilobe rotating member between said wheels, coaxial therewith, each lobe thereof providing a pair of stop surfaces corresponding to the closed and open positions of each of said hammer drivers,

(d) a pivotally-mounted interposer carrier having a bifurcated end positioned adjacent to said circular path,

(e) an interposer slidably mounted in the bifurcated end of said interposer carrier,

(f) and means to move said interposer into said circular path between saidhammer and a selected one of said hammer drivers, said interposer operating to cause-said selected hammer driver to move said hammer against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carrying means and said hammer, and operating to cause said selected hammer driver to move from said closed position to said open position, allowing the removal of said interposer from between said hammer and said selected hammer driver after the printing of said'selected character.

7. In a high-speed printer,

(a) means carrying a plurality of characters past a printing position,

(b) a rotating hammer driver assembly synchronized with said character-carrying means comprising a pair of coaxially spaced similar'rotating wheels, a plurality of hammer drivers pivotally mounted between said wheels at spaced positions adjacent the peripheries of said wheels and carried along a circular path, said hammer drivers movable between a closed position and an open position, centrifugal forces developed in said hammer drivers by hammer driver assembly rotation normally retaining said hammer drivers in said closed position, and a multi lobe rotating member between said wheels, coaxial therewith, each lobe thereof providing a pair of stop surfaces for each of said hammer drivers corresponding to said closed and open positions, (0) a pivotally-mounted interposer carrier positioned adjacent to said circular path,

(d) an interposer slidably mounted in said interposer carrier,

(e) a printing hammer pivotally mounted and resiliently biased to a position in which one end of said hammer is adjacent to said printing position and its other end is against said interposer carrier,

(1) and means to move said interposer between said hammer and a selected one of said hammer drivers,

said interposer operating to cause said selected hammer driver to pivot said hammer, with the end of said hammer adjacent to said printing position being moved against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carrying means and said hammer.

8. In a high-speed printer, (a) means carrying a plurality of characters past a printing position,

(b) a printing hammer adjacent to said printing position adapted to urge data-receiving means against said characters,

(c) a rotating element synchronized with said character-carrying means,

(d) a plurality of stop elements associated with said rotating element, providing a plurality of pairs of stop surfaces,

(e) a plurality of hammer drivers pivoted on said rotating element and held inwardly by centrifugal force against one stop surface of an associated pair of said stop surfaces,

(1) an interposer positioned adjacent to said hammer and said rotating element so that it can move between said hammer and a selected one of said hammer drivers,

(g) and means to move said interposer between said hammer and a selected one of said hammer drivers, said interposer moving means comprising an electromagnet, an armature coupled to said interposer and normally held by said electromagnet away from said rotating element, and means resiliently urging said armature towards said rotating element, said electromagnet being responsive to an electrical print signal to allow said urging means to move said armature adjacent to said rotating element whereby said interposer is moved between said hammer and said selected hammer driver, said interposer, upon being moved between said hammer and said selected hammer driver, causing said selected hammer driver to move from said one stop surface and to move said hammer against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carrying means and said hammer, and causing said selected hammer driver to be pivoted outwardly from said rotating element against the other stop surface of said associated pair resulting in the removal of said interposer from between said hammer and said selected hammer driver and the movement of said armature away from said rotating element whereupon said armature is again held by said electromagnet away from said rotating element after the printing of said selected character.

9. In a high-speed printer, (a) means carrying a plurality of characters past a printing position,

(b) a printing hammer adjacent to said printing position adapted to urge data-receiving means against said characters,

() a rotating hammer driver assembly synchronized with said character-carrying means comprising a pair of coaxially spaced similar rotating wheels, a plurality of hammer drivers pivotally mounted between said wheels at spaced positions adjacent the peripheries of said wheels and carried along a circular path, said hammer drivers movable between a closed position and an open position, centrifugal forces developed in said hammer drivers by hammer driver assembly rotation normally retaining said hammer drivers in said closed position, and a multilobe rotating member between said wheels, coaxial therewith, each lobe thereof providing a pair of stop surfaces for each of said hammer drivers corresponding to said closed and open positions,

(d) a pivotally-mounted interposer carrier positioned adjacent to said circular path,

(e) an interposer slidably mounted in said interposer carrier,

(f) and means to move said interposer into said circular path between said hammer and a selected one of said hammer drivers, said interposer operating to cause said selected hammer driver to move said hammer against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carrying means and said hammer, and operating to cause said selected hammer driver to move from said closed position to said open position resulting in the removal of said interposer from between said hammer and said selected hammer driver after the printing of said selected character, said interposer moving means comprising an electromagnet, a pivotally mounted armature coupled to said interposer, and means resiliently urging said armature towards said hammer driver assembly, said electromagnet normally restraining said armature whereby said interposer is held away from said circular path, said electromagnet being responsive to an electrical print signal to allow said urging means to move said armature towards said circular path whereby said interposer is moved between said hammer and a selected one of said hammer drivers.

10. In a high-speed printer,

(a) means carrying a plurality of characters past a printing position,

(b) a printing hammer adjacent to said printing position adapted to urge data-receiving means against said characters,

' (c) a rotating hammer driver assembly synchronized with said character-carrying means comprising a pair of coaxially spaced similar rotating wheels, a plurality of hammer drivers pivotally mounted between said wheels at spaced positions adjacent the peripheries of said wheels and carried along a circular path, said hammer drivers movable between a closed position, in which a hammer driver extends outwardly a first distance beyond the peripheries of said wheels, and an open position, in which a hammer driver extends a second distance, greater than said first distance, beyond the peripheries of said wheels, centrifugal forces developed in said hammer drivers by hammer driver assembly rotation normally retaining said hammer drivers in said closed position, and a multilobe rotating member between said wheels, coaxial therewith, each lobe thereof providing a pair of stop surfaces corresponding to the closed and open positions of each of said hammer drivers,

(d) a pivotally-mounted interposer carrier having a bifurcated end positioned adjacent to said circular p (e) an interposer slidably mounted in the bifurcated end of said interposer carrier,

(1) and means to move said interposer into said circular path between said hammer and a selected one of said hammer drivers, said interposer operating to cause said selected hammer driver to move said hammer against said character-carrying means resulting in the printing of a selected character on said datareceiving means interposed between said charactercarrying means and said hammer, and operating to cause said selected hammer driver to move from said closed position to said open position resulting in the removal of said interposer from between said hammer and said selected hammer driver after the print ing of said selected character, said interposer moving means comprising an electromagnet, a pivotally mounted armature coupled to said interposer, and means resiliently urging said armature towards said (b) a printing hammer adjacent to said printing position adapted to urge data-receiving means against said characters,

() a rotating element synchronizedwith said character-carrying means,

(d) a plurality of stop elements associated with said rotating element, providing a plurality of stop surfaces,

(e) a plurality of hammer drivers pivoted on said rotating element, each hammer driver being held inwardly by centrifugal force against a separate one of said stop surfaces,

(f) an interposer positioned adjacent to said hammer and said rotating element so that it can move be tween said hammer and a selected one of said hammer drivers,

(g) andmeans to move said interposer between said hammer and a selected one of said hammer drivers, said interposer moving means comprising an electromagnet, an armature coupled to said interposer and normally held by said electromagnet away from said rotating element, and means urging said armature away from'said electromagnet towards said rotating element, said electromagnet being responsive to an electrical printing signal to cause release of said armature thereby allowing said urging means to move said armature towards said rotating element, whereby said interposer is moved between said hammer and a selected hammer driver, said interposer upon being moved between said hammer and said selected hammer driver causing said selected hammer driver to move from its stop surface and to move said hammer against said character-carrying means resulting in the printing of a selected character onsaid datareceiving means interposed between said charactercarrying means and said hammer, said selected ham mer driver, after moving said hammer against said character-carrying means, causing said interposer to be removed from between said hammer and said selected hammer driver thereby causing said arma- (c) a rotating hammer driver assembly synchronized with said charactencarrying means comprising a pair of coaxially spaced similar rotating wheels, a pinrality of hammer drivers pivotally mounted between said wheels at spaced posit-ions adjacent the peripheries of said wheels and carried along a circular path, said hammer drivers movable between a closed position and an open position, centrifugal forces developed in said hammer drivers by hammer driver assembly rotation normally retaining said hammer drivers'in said closed position, and a multilobe rotating member between saidwheels, coaxial therewith, each lobe thereof providing a pair of stop surfaces for each of said hammer drivers corresponding to said closed and open positions, (d) a pivotal-ly-mounted interposer carrier positioned adjacent to said circularpath,

(e) an interposer slidably mounted in said interposer carrier,

(f) and means to move said interposer into said circular path between said hammer and a selected one of said hammer drivers, said interposer moving means comprising an electromagnet, a pivotally-mounted armature coupled'to'said interposer and normally held by said electromagnet away from said circular path, and means resiliently urging said armature towards said hammer driver assembly, said electromagnet being responsive to an electrical print signal to cause release of said armature thereby allowing said urging means to move said armature towards said hammer driver assembly whereby said interposer is moved into said circular path between said hammer and said selected hammer driver, said interposer upon being moved between said hammer and said selected hammer driver causing said selected hammer driver to move said hammer against said character-carrying means resulting in the printing of a selected character on said data-receiving means interposed between said character-carryingmeans and said hammer, and causing said selected hammer driver to be moved from said closed position to said open position, said selected hammer driver in moving from its closed position to its open position operating to remove said interposer fromsaid circular path thereby causing said armature to be moved away from said hammer driver assembly and adjacent to said elemtromagnet whereupon said armature is again held by said electromagnet away from said hammer driver assembly and said interposer is maintained out of said circular path after the printing of the selected character.

References Cited by the Examiner UNITED STATES PATENTS 2,766,686. 10/56 Fomenko et a1. 10l93 2,895,411 7/59 Demer et a1. 101'93 2,897,752 8/59 Malmros et a1. 10l93 2,949,846 8/60 Hoffman et a1. 10193 3,049,990 8/62 Brown et al'. l01-93 WILLIAM B. PENN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No a 3,175, 487 March 50, 1965 Arthur B. Braden, Jr, et al.

he above numbered patt error appears in t Patent should read as It is hereby certified-the said Letters ent requiring correction and that the corrected below.

read -C0axially line 44, for "axially" read electromagnet e.

Column 7,

for "elemtromagnet columnlZ, line 48,

c1 and sealed this 24th day of August 1965.

Signe (SEAL) Altest:

EDWARD J. BRENNER. 

1. IN A HIGH-SPEED PRINTER, (A) MEANS CARRYING A PLURALITY OF CHARACTERS PAST A PRINTING POSITION, (B) A PRINTING HAMMER ADJACENT TO SAID PRINTING POSITION ADAPTED TO URGE DATA-RECEIVING MEANS AGAINST SAID CHARACTERS, (C) A ROTATING ELEMENT SYNCHRONIZED WITH SAID CHARACTER-CARRYING MEANS, (D) A PLURALITY OF STOP ELEMENTS ASSOCIATED WITH SAID ROTATING ELEMENT, PROVIDING A PLURALITY OF PAIRS OF STOP SURFACES, (E) A PLURALITY OF HAMMER DRIVERS PIVOTED ON SAID ROTATING ELEMENT AND HELD INWARDLY BY CENTRIFUGAL FORCE AGAINST ONE STOP SURFACE OF AN ASSOCIATED PAIR OF SAID STOP SURFACES, (F) AN INTERPOSER POSITIONED ADJACENT TO SAID HAMMER AND ROTATING ELEMENT SO THAT IT CAN MOVE BETWEEN SAID HAMMER AND A SELECTED ONE OF SAID HAMMER DRIVERS, (G) AND MEANS TO MOVE SAID INTERPOSER BETWEEN SAID 